Safety interlock for the access door of washing and the like machines



Oct. 27, 1970 A. K. BROWN ET AL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND 4 THE LIKE MACHINESFiled Oct. 18 1968 6 Sheets-Sheet 1 n7 na- Oct. 27, 1970 A. K. BROWN ETAL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS vDOOR OF WASHING AND THE LIKE MACHINESFiled Oct. 18. 1968 6 Sheets-Sheet 2 Oct. 27, 1970 A. K. 5mm E ZT AL3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND THE LIKE MACHINES 6Sheets-Sheet 3 Filed Oct. 1 8. 1968 3 2 1 I W Q. Q I 8 1% fi s Q ll J$7: 1 n: N :v Q 4 2 H mm MELT :EIWS T a 6 N o 1| o itilfiqiwlt Q H L 8m2 a 8 3 S 3M 2 A. K. BROWN L Oct. 27, ,1970

SAFETY INTERLOCK FOR THE ACCESS DOOR 0F WASHING AND' THE LIKE MACHINES 6Sheets-Sheet 4 Fild 001;. 18. 1968 Oct. 27, 1970 A. K. BROWN ETAL3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHINGAND THE LIKE MACHINESFlled Oct. 18, 1968 6 Sheets-Sheet 5 gl03 NR3 S'W'd' 63 7e In l m 426a4b 1' A. T

2O x i 4 7 Wash Winding 7 v Ls A I I 7E 3.: N Fig) 65 DoorSwifch 06:.27, 1970 A K. BROWN ETAL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND THE LIKE MACHINESFiled Oct. '18, 1968 6 Sheets-Sheet 6 United States Patent US. Cl. 68126 Claims ABSTRACT OF THE DISCLOSURE A clothes washing or other machine,of the kind in which articles to be treated are placed in a drumprovided with an access opening and the drum is rotatable by an electricdrive motor comprising an automatic programme sequence control, aninterlock arranged to prevent opening of the door, as by preventingoperation of a door opening knob, except when a selected operation hasbeen completed, a manually operable control knob for by-passing anoperation, as by accelerating movement of a face cam normally driven bya timer motor of the automatic programme sequence control, but only upto a period before the end of the by-passed operation, at which stagethe manually operable means becomes ineffective for that purpose and theremainder of the operation is controlled by the timer motor, this periodcorresponding to that for the drum to come to rest and liquid to bepumped from the drum to enable safe opening of the door.

BACKGROUND OF THE INVENTION This invention relates to washing machines,spin dryers or like machines in which articles to be treated are placedin a drum provided with an access opening and rotatable by an electricdrive motor.

Such machines are normally provided with a door hingedly connected to anouter housing of the machine and a fastening device on the door isarranged to cooperate with a safety latch on the housing so that thedoor cannot be opened unless operation of the machine has first beeninterrupted or terminated. Such a safety arrangement often comprises asolenoid actuated lock energised in parallel with the drive motor forthe drum and operating so that when the drive motor is deenergised thedoor can be opened. This arrangement is not entirely satisfactory as itis possible to open the door while the drum, although decelerating, isstill rotating at a comparatively high speed.

In machines, such as washing machines of the horizontal type, in whichtreatment of clothes consists of a series of operations performed in adrum rotating on a horizontal or substantially horizontal axis, the drumhaving an access opening, normally closed by the door in one wall, thereis a further disadvantage in that liquid from the drum may be spilled ifthe door is opened during rotation of the drum. The operation of suchmachines, particularly washing machines, is usually controlled by asequence control, i.e. electrical devices included in the machine areconnected via a mechanism comprising a plurality of switches, to asource of electricity supply, and the switches are actuated either insequence by automatic means or, manually if it is desired that anyoperation in the sequence be terminated or omitted. It is usual thereforto provide a door interlock coupled to the sequence control, such thatthe door remains locked in all positions of the sequence control exceptthose where the drum should be empty of liquid and stationary. Inproviding this alternative control, however, it is possible by manualadvancement of the switches 3,535,896 Patented Oct. 27, 1970 throughtheir set sequence to a point where the door is unlocked for the door tobe opened either with the drum rotating at high speed, or containingliquid, as insufiicient delay is then provided for the drum to come to arest, or be drained of liquid.

SUMMARY OF THE INVENTION An object of this invention, therefore, is toprovide a safety interlock for the access door such that thesedisadvantages are overcome. I

According to the present invention in a washing machine, spin dryer orthe like machine in which articles to be treated are placed in a drumprovided with an access opening and rotatable by an electric drivemotor, the drum opening being fitted with a door, there is provided anautomatic sequence control which is also capable of man ual actuation inorder that an operation or operations may be by-passed, an interlockbeing arranged to prevent opening of the door at all times, except wheneach or a series of operations have been finally completed, by inclusionof means on manual operation providing a delay period sufficient toallow the door to be opened safely, and the arrangement being such thatmanual actuation of the control is rendered ineffective to override thisdelay period as by ensuring that the last part of the operation oroperations by-passed is controlled by a timer motor.

Since the invention is of particular value in its application to clothesWashing machines particularly of the horizontal type, i.e. in whichtreatment of the clothes is carried out in a forarninous electric motordriven rotatable drum, whose axis is horizontal or substantiallyhorizontal, and which drum is mounted within an outer coaxial washliquid containing drum suspended in a cabinet by means of springs anddampers its applications thereto will now be further described.

A typical series of treatment operations in such a machine may consistof: a washing period, in which the clothes drum is rotated forsubstantially equal periods of time in each direction to tumble theclothes in contact with a washing liquid contained within the outerdrum; a spinning period, during which the clothes drum is rotated athigh speed in one direction only to centrifugally extract the washingliquid from the clothes, a pump being used to remove the resultingliquid from the drums; a rinse period, the operation being similar tothat during the wash period but the washing liquid being replaced byWater, with or without a rinsing additive; and a final, further spindrying period. Such a programme can be effected by a sequence controlmounted in the machine cabinet which, by means of switches sequentiallyactuated in response to movement of a synchronous electric timing motor,causes energization of the drive motor(s) and other ancillary electricalcomponents of the machine to perform the programme as laid out.Associated with the sequence control may be a scale on which anindicator, connected to the timer, presents the progress of theprogramme.

A door latch mechanically operated by a button on the control panel ofthe machine is arranged to be locked by the sequence control at alltimes except when it is safe and desirable to open the door, i.e. whenthe drum is stationary and empty of water. A setting knob associatedwith the control also allows manual advancement of the sequence at alltimes except to immediately prior to any point where the control wouldpermit operation of the door latch to open the door. At these points theknob is arranged to be disengaged and the control advances independentlyfor a predetermined period so providing the delay in which the rotatinginner drum can come to rest giving time for any liquid present in thedrums to be removed by the pump before the door can be unlatched.

- 3 BRIEF DESCRIPTION OF THE DRAWINGS Reference will now be made by wayof example to the accompanying drawings, in which:

FIG. 1 is a front view of a horizontal washing machine with its accessdoor closed.

FIG. 2 is a part plan view of the washing machine of FIG. 1,

FIG. 3 is a part sectional elevation of FIG. 1 of the washing machine.

FIG. 4 is a bottom plan view of a control panel of the washing machineof FIG. 1 with its electric motor operated sequencer timer omitted,

FIG. 5 is a vertical side-to-side cross section of part of the controlpanel of FIG. 4 showing the electric motor operated sequence timer andits control knob,

FIG. 6 is a perspective view of a part of the sequence timer,

FIGS. 7 & 8' are sectional bottom plans of further detailed views of thecontrol of FIG. 5,

FIG. 9 is a vertical front-to-rear section of part of the access door ofthe machine and its associated latching mechanism,

FIG. 10 is a circuit diagram of the washing machine, and

FIG. 111 is a time cycle chart of the washing machine programme.

In FIGS. 1-3 there is shown a horizontal washing machine comprising anouter liquid container 101 mounted on four damped spring suspension legstwo only of which are shown at 102 within an outer cabinet 103-, and aninner perforate horizontal clothes drum 104 mounted for rotation on aspider 105 at the rear of the drum 104. The spider 105 is rigidlysecured to a driven shaft 106 rotatable in horizontal spaced bearings107, and 108 in a bearing housing 1109 secured to the rear of the liquidcontainer. The arrangement of the spaced bearings 107, 108 acting on thedrive shaft 106 allows the drum to be supported at that, Le. the 'back,end only. The driven shaft 106 carries a pulley 110 drivingly secured toit. A drive belt 111 of V section extends round the pulley 1'10 and apulley F112 carried by an output shaft 113 of a two-speed electricinduction motor 114 which is supported at each end of its casing bymeans of suspension units 115 and 116 from the lower part of the outerliquid container 101. Access by a user to the clothes drum 104 isobtained through a front door 117 hinged at 118 and 119 (FIG. 1).

Liquid is supplied to the drums 101 and 104 through anelectromagnetically actuated water inlet valve 120 (FIG. 3). A liquidlevel responsive switch 126A shuts the water inlet valve when the waterlevel in containers 101 and 104 reaches the required level and initiatesactual washing. Liquid in the drum is heated where required by theprogramme sequence by a sheathed wire electric resistance heater 121mounted towards the bottom of the drum 101 and is removed from the drum101 by a pump 122 driven by its electric motor 123 through a pipe 124only partly shown in FIG. 3, but extending from the rear bottom of thedrum 101 to the pump 122.

A washing machine control panel 125 is provided on the top of thewashing machine at its front and includes a sequence timer 1 (FIG. 5)having a synchronous electric driving motor 2, which in operationrotates through a set of pawls and gears in a gear case shown at 4, ashaft 5 in a stepwise fashion. Successive steps conveniently occur atintervals of two minutes to enable easy and accurate allocation ofactive periods of a programme of the washing machine. A face cam 6mounted on the shaft 5 to rotate with the shaft so as to selectivelyenergise and de-energise various electrical components of the washingmachine through switches indicated generally at 7 such that it willperform the operations described in the preamble hereto.

A disc 8 is also fixed to the shaft 5 and rotates with the shaft and hasa form as more clearly shown in FIG. 6,

including an annular flange 8a and gear teeth 9; the various functionsof this disc will be described hereinafter. A manual control knob 10 forthe timer 1 is rotatably mounted on the shaft 5 and retained thereon bya locknut 11 and a circular trim member 12 decoratively covers theotherwise open front of the knob. The control knob 10 has four radialprojections shown at 10a (FIGS. 5, 7 and 8) which act in conjunctionwith a lever 13 of semirigid material, such as nylon, of the form shownin FIGS. 7 and 8. and pivotally mounted on a pin 14- on the underside ofdisc '8. One end 13b of the lever 13 is attached to a coil tensionspring 15 the opposite end of which is anchored at pin 15a so that theother end 13a of the lever is capable of limited movement in an arcuatemanner about the pin 14 thus under the restraining influence of thespring 15.

A projection 16 on the arm 13a of the lever passes through a slot 17 inthe disc 8 (see also FIG. 5) so as to co-operate with one or the otherof the projections 10a. A further part 18 of the lever 13 is arranged toengage with an internal surface 19a of an annular cam 19 and inparticular with recess. 1%.

The gear teeth 9 formed around part of the periphery of disc 8 (FIGS. 4,6, 7 and 8) engage with teeth of similar form on a gear wheel 20 (FIGS.4 and 5) which is ro-- tatably mounted on a pin 21 attached to a controlpanel supporting plate 22.

A drive cord 24 (FIG. 4) for a scale indicator pointer 25' passes roundthe periphery of a drum 26 integral with the gear wheel 20 and issecured thereto. The drive cord 24 slidably passes over pins 28a, 28b,28c and 28d (FIG. 4) which are fixed to the control panel supportingplate, to a pulley 30 attached to a tensioning spring 31 and from thepulley 30 the drive cord 24 returns to the pin 28d to which it issecured. The pointer 25 is fixedly secured by turned over projections onthe pointer 25 to the portion of the drive cord 24 between pins 28b and280 and overlies a scale 33 marked with indications of the variousselectable programme of the washing machine.

The upstanding annular flange 8a of disc 8 (see FIGS. 48) has a portion8b cut away sufficiently to allow introduction of a latch 35 (FIG. 4) ofa lever 36 pivoted on a pin 37 on the control panel supporting plate 22.The lever 36 is formed from a semirigid material, such as nylon, and hasa portion 38 of thinner crosssection forming a spring which bearsagainst an upturned portion 22a of the supporting plate in a manner suchthat the latch 35 is urged away from the annular flange 8a. The lever 36is also pivotally connected at 36:; to one end of a rod 39, the oppositeend 390 of which is pivotally attached to one arm of a bell crank 40pivoted on a pin 41 on the supporting plate. The other arm of the bellcrank 40 is pivotally attached to a further rod 42 at 42a an oppositeend 42b of which carries a shorter arm of a lever 43, pivoted on a pin44 on the supporting plate. The longer arm of the lever 43 has attachedthereto, close to the pivot point 44, an inner wire of a Bowden cable45, which is anchored to the supporting plate by a bracket 46-. Thelonger arm of the lever 43 also bears on a knob 47 (FIGS. 2 and 4)accessible from outside and slidably held within an open ended box 48secured to the supporting plate.

The other end of the Bowden cable 45 is connected to a latchingarrangement 126 for the washing machine door as shown in detail in FIG.9. A latch arm 49 of the latching arrangement is pivoted at 4911 in amoulded housing 51 secured by nuts and bolts 52 to the front wall of themachine shown in part at 103. The latch arm 49 engages at one end with alatch plate 54 which is formed integrally with an inner panel 56 of thewashing machine door 117 as shown in FIG. 9. A rubber resilient sealinggasket 58 is provided between the door and the front wall 103. Theconnection to the latching arrangement is by the Bowden cable inner wire45a being connected to the end of the latching arm 49 opposite the door,while the outer casing 45b of the cable is secured to the mouldedhousing 51. A spring 59 retains the latching arm 49 in the positionshown in FIG. 9 until actuated by the Bowden cable.

The control panel carries a further knob 60, held captive in the samemanner as knob 47 by a box 61, which box is equipped with a latchingspring 62 and is arranged to operate a microswitch 63 secured to thesupporting plate 22 by screws 64. The microswitch 63 controls a step inthe programme as will be described hereinafter.

To load the machine with articles to be washed etc. the access door 117is opened by pressing the knob 47 to pivot the lever 43 about its pivot44, thereby actuating the Bowden cable 45 so as to rotate the latch arm49 in an anti-clockwise direction and release the latching arrangementto allow the door 117 to spring open under the influence of theresilient gasket 58. The pivoting of the lever 43 simultaneously shiftsrod 42 so as to rotate the bell crank 40 and supply a compressive forceto the rod 39 causing the lever 36 to rotate in a clockwise direction(in FIG. 4). As a result, the latch member 35 is moved into the cut out8b in the annular flange 8a.

The clothes to be washed can be inserted into the inner rotatable, drum104 and the access door 117 closed compressing the gasket 58 andre-engaging the latch plate 54 with the latch arm 49. A washingoperation is started by (rotating the timer knob clockwise to thedesired programme position thereby locking the door and then) pullingthe timer knob 10 outwards thereby closing an isolating switch 65 (FIG.10) associated with the timer so as to supply electrical power throughthat one of the switches 7 closed by the face cam 6 to start the timermotor 2 i.e. 7a.

The timer motor 2 commences to rotate the shaft 5 and with it the facecam 6 and disc 8 in a stepwise motion at intervals of 2 minutes, theshaft 5 performing one complete revolution in the course of a normalprogramme. The first programme step is such as to rotate drum 8 from theposition shown in FIG. 4 so that the cut out 8b in the annular flange 8aceases to coincide with the latch 35 and movement of the knob 47inwardly to actuate the door unlatching mechanism is thereby baulked byengagement of the latch member 35 against the annular flange 8a. Thedoor cannot therefore be unlatched throughout the programme until thecut out 8b again coincides with the latch 35; such coincidence onlyoccurring at the end of the programme i.e. when the machine isdeenergised. The first stepwise motion of the shaft also causes face cam6 to close that one of the switches 7 necessary to commence theprogramme i.e. switch 7a to open the water inlet solenoid valve.

If the programme of the machine is not now manually altered by a user,operation of the timer will cause the machine to carry out its setprogramme as illustrated in the timer cycle chart FIG. 11 and asdetermined by the rotation of the face cam 6 and the distribution of theswitches 7 and circuit FIG. 10. The progress of the pro gramme isrecorded by movement of the pointer 25 as it is moved by the cord 24 inaccordance with movement of the gear and hence with the movement of thedisc 8. As the programme proceeds the pointer 25 traverses the scale 33and the spring 31 is tensioned. Four minutes, or two steps, before theend of the programme, i.e. the last two minutes of spinning, followed bydeenergisation of the drive motor the clothes drum coasts to a halt, adrain pump remaining energised to ensure removal of free liquid from thedrums. At the end of the programme the last stepwise motion of the shaft5 rotates the disc 8 to a position in which the toothed portion 9disengages from gear 20 due to a gap in the gear teeth on disc 8 and thepointer 25 is thus returned to its original position under the influenceof spring 31. The same last step deenergises the drain pump and alsobrings the cut out 8b once again into line with the latch 35 to permitunlatching of the access door 117 of the machine so as to allow removalof the washed clothes.

If, for any reason, the user wishes to by-pass any particular operationin the programme this is achieved by first pushing knob 10 inwards,thereby opening the switch 65 and de-energising the machine. The knobcan then be rotated in a clockwise direction causing the radialprojection 10a to engage with the projection 16 of lever 13 in FIG. 7;this projection 16 is therefore urged in a clockwise direction and thusacts against the pivot pin 14 causing the disc 8 and hence the timershaft 5 to rotate with knob 10. The programme is thus advanced inresponse to the rotation of the printed circuit board 6, the pointer 25moving to indicate the progress through the programme. When the desiredoperation is reached the knob 10 is pulled outwards to close the switch65 and the programme is thereby re-started at a selected point. If theuser desires to terminate the programme before it has run its coursethis can be achieved by pushing the knob 10 inwards to deenergise themachine and by rotating the knob 10 to move the programme towards itscompletion as described above.

In both these cases, in order to ensure that the access door 117 is notopened before the clothes drum 104 has coasted to a halt or before thedrain pump 122 has removed all the water from the drums, a delay periodis introduced at the end of the programme sequence during which theaccess door 117 cannot be unlatched. This is achieved by providing thatas the programme progresses towards its completion, part 18 of the lever13 is urged by spring 15 into recess 19]) four minutes or two steps,before the end of the programme. The lever 13 thus moves outwards andprojection 16 no longer co-operates with radial projection 10a on theknob 10 which is thus free to rotate on shaft 5 without influencing theprogramme sequence. The last four minutes of the programme are thuscontrolled entirely by timer motor 2 and cannot be by-passed orterminated by movement of the control knob. By this means it is ensuredthat the rotating clothes drum has ample time to coast to a halt andthat the drain pump 122 has cleared the drums 101 and 104 of washingliquid before the timer shaft 5 rotates to bring the cut out 8b intocoincidence with the latch 35 and thus permit the door to be opened byoperation of the knob.

While the programme sequence described provides only one position inwhich the door may be unlatched, the construction of member 8 may bealtered to permit the access door 117 to be opened at various otherpoints in the programme, where it is safe to do so. For example, aperiod could be incorporated immediately before the rinsing operation,during which the door could be opened for the insertion into the drum ofclothes requiring only a single washing or rinsing operation, additionalcut outs being incorporated in member 19 to disconnect the knob 10 atleast one programme step before the end of the previous period asbefore.

For clothes which should not be spin dried the knob 60 is provided,which, when operated so as to actuate the microswitch 63, preventsrotation of the drum at spinning speed by overriding the controllerwhich would otherwise cause energisation of the drive motor at spinningspeed. Operations in the programme sequence normally designated for spindrying are thus, by operation of the knob 60, devoted only to removing,by means of the drain pump, water which drains from the clothes duringthat period.

If the invention is to be applied to a vertical washing machine, inwhich the washing operation is performed in a drum with a vertical axis,by agitation of the clothes and washing liquid by a reciprocating paddleor rotating impellor, and in which drying is performed by high speedrotation of the drum about its vertical axis, then the cut out in theannular flange 8a can be extended to permit unlatching of the accessdoor at all times except during the actual spin drying operations andone programme step thereafter in which to permit the rotating drum tocoast to a stop. There is no risk of water escaping in such a machine,if the access door, which is normally at the top of the machine casingis opened during the washing operation.

An application of such a safety feature to a machine intended solely forcentrifugally drying clothes by fast rotation about a vertical axiscould also be provided for by a controller having only a single controlswitch, for a motor in conjunction with a door interlock and a knobdisengaging device as already described.

Although the time intervals (FIG. 1) are conveniently 2 minute onesother intervals may be used, e.g. 1% minutes.

What we claim is: I

1. A machine of the kind in which articles to be treated are placed in adrum provided with an access opening and the drum isrotatable by anelectric drive motor, comprising an automatic sequence control, aninterlock arranged to prevent opening of an access door fitted to tionprior to the end of the bypassed operation, the knob the drum openingexcept when a selected operation has been completed, and manuallyoperable means for bypassing an operation, in which time delay means areprovided which prevent release of the interlock until a safe periodafter the manually operable means has been used to by-pass theoperation.

2. A machine as claimed in claim 1, in which a latch for the door ismechanically operable by a button on a control panel of the machine andthe interlock prevents operation of the button except when it is safeand desirable to open the door.

3. A machine as claimed in claim 1, in which the manually operable meansis arranged to accelerate movement of a timing part normally driven by atimer motor of the automatic sequence control but only up to a periodbefore the end of the bypassed operation, at which stage the manuallyoperable means become ineffective for that purpose and the remainder ofthe operation is controlled by the timer motor. 1

4. A machine as claimed in claim 3, in which a programme setting knoband associated parts constitute the manually operable means and they arearranged in a condition of the knob to advance the sequence to aposithen being ineffective to advance the programme.

5. A machine of the kind as claimed in claim 4, in which the programmesetting knob is in the condition set forth in claim 4, arranged toinitially open a main switch deenergising the machine and on furthermovement cooperating abutment surfaces, one being movable by the knoband the other being provided on a timing shaft of the sequence controlare arranged to engage so as to accelerate the timer through anoperation, means being provided which before the end of the operationdisengage the drive from the timer shaft so that the knob turns freelywithout overriding the operation which is then under control of theautomatic sequence control.

6. A machine as claimed in claim 1, in which the drum is arranged torotate about a horizontal or substantially horizontal axis and the drumis arranged to contain liquid for treating the articles in the drum and,in which the delay period provided after the operation of the manuallyoperable means to bypass the sequence control is such as to allow boththe drum to come to rest and for any liquid present to be removed by apump before the door can be unlatched.

References Cited ROBERT L. BLEUTGE, Primary Examiner US. Cl. X.R.

4/1966 Switzerland.

